The spell ends if the ring is removed
=
*Warding bond* has a very specific material component.

The section on [material components](https://www.dndbeyond.com/forums/dungeons-dragons-discussion/rules-game-mechanics/3120-material-components-for-spells) states:
> ...if a cost is
indicated for a component, a character must have that
specific component before he or she can cast the spell.

As a general rule, I would say that once a spell is cast, the materials used to cast it no longer need to be considered. However, [*warding bond*](https://www.dndbeyond.com/spells/warding-bond) is different from other spells in this wording on the material component (emphasis mine):
>a pair of platinum rings worth at least 50 gp each, which you and the target **must wear for the duration**

I would rule this as a case of specific-beats-general in that the use of the word "must" indicates that the duration is directly linked to the ring being worn, and thus **the spell ends immediately upon removal of the platinum ring(s)**.